Evaluation and Management of Crescendo-Decrescendo Murmurs

Innocent Murmurs

The American College of Cardiology recommends that a grade 1-2 intensity murmur at the left sternal border with normal S2 splitting and no other abnormal findings in a young individual requires no further workup 1, 2, 3
Innocent murmurs are characterized by a grade 1-2 intensity at the left sternal border 1, 2, 4
Normal S2 intensity and splitting are typical of innocent murmurs 3, 4
No radiation to neck or back is a characteristic of innocent murmurs 1, 2

Aortic stenosis is a pathologic cause of a crescendo-decrescendo murmur that radiates to the neck 1, 2, 5
Hypertrophic cardiomyopathy is a pathologic cause of a crescendo-decrescendo murmur that increases with Valsalva or standing 4

The American College of Cardiology recommends grading the intensity of the murmur (1-6 scale for systolic murmurs) 3, 4
Assessing radiation (neck, back, axilla) is an important part of the diagnostic approach 1, 2
Evaluating S2 splitting (normal vs. fixed/paradoxical) is crucial in determining the cause of the murmur 3, 4
Listening for ejection clicks can suggest valvular stenosis 1, 2

A grade 3 or louder murmur is a red flag that requires immediate echocardiography 1, 2, 3
Radiation to neck or back is a red flag that requires further evaluation 1, 2, 3
Associated ejection click is a red flag that requires further evaluation 1, 2, 3
Abnormal S2 (widely split, fixed, or paradoxical) is a red flag that requires further evaluation 4
Symptoms such as syncope, chest pain, dyspnea, heart failure, or palpitations are red flags that require further evaluation 1, 2, 3

No treatment is required for innocent murmurs 1, 2, 4
Management of pathologic murmurs depends on the specific diagnosis from echocardiography 1, 2
Severe aortic stenosis requires surgical or transcatheter valve replacement 1
Hypertrophic cardiomyopathy requires beta-blockers, activity restriction, and ICD consideration 4

A normal echocardiogram in a patient with a cardiac murmur indicates either an innocent/physiological murmur or trivial valvular regurgitation, both of which are benign findings that require no intervention, according to the American College of Cardiology 6, 7
Trivial or minimal valvular regurgitation is detected by color flow imaging in many otherwise normal patients, including those without any audible murmur, and should not prompt referral in asymptomatic patients, as recommended by the American College of Cardiology 6, 7
The American College of Cardiology suggests that if new symptoms develop, such as syncope, chest pain, or dyspnea, repeat evaluation is warranted regardless of prior normal echo 7
A comprehensive and adequate quality echocardiogram is necessary to visualize all cardiac structures and confirm no structural disease, as stated by the American College of Cardiology 6
High-output states, such as anemia or pregnancy, can cause functional murmurs that resolve when the underlying condition is treated, and a normal echo in these contexts confirms no structural disease, according to the American College of Cardiology 6, 7
The American College of Cardiology recommends that no specific cardiac follow-up is required for asymptomatic patients with murmurs and normal echocardiograms, and patient reassurance is appropriate, explaining that the murmur represents either normal blood flow sounds or trivial valve leakage that has no clinical significance 6, 7